The embodiments described herein relate generally to valve assemblies and, more particularly, to a valve assembly for use with a washing appliance, such as a dishwasher.
In at least some known dishwashers, it is desirable to reduce water consumption to conserve energy and/or water. For known dishwashers, there is a minimum amount of water that enables the dishwasher to properly pump water to wash items within a tub of the dishwasher. Such an amount of water is referred to herein as “a minimum amount,” which includes some variation from a calculated minimum amount of water that enables a dishwasher to function properly. Any amount of water that is more than the minimum amount of water is referred to herein as “extra water.” When less water than the minimum amount of water is used, performance of the dishwasher may decrease and/or noise generated by the dishwasher may increase. Accordingly, a water supply valve of the dishwasher is controlled to provide at least the minimum amount of water to the tub.
At least some known dishwashers include water supply valves that are controlled to be open for a fixed, predetermined time to enable a predetermined amount of water to be channeled into a tub of the dishwasher. Each cycle of activating and deactivating the valve is referred to herein as a “fill cycle.” A wash cycle may include a plurality of fill cycles. In at least some known dishwashers, such water valves are controlled by mechanical timers and/or system controllers that turn power to the valve on and off during a wash cycle.
Known mechanical timers activate the valve, count an amount of time, and deactivate the valve after a predetermined duration of time during each fill cycle. The mechanical timer and valve assembly may deliver an inaccurate amount of water to the tub due to variations in flow rate through the valve and variations in the accuracy of the mechanical timer. For example, the mechanical timer may activate for 60 seconds (sec) with a variation of at least +/−6 sec. In at least some known dishwashers, the variation in the accuracy of the mechanical timer can account for more than 50% of the variation in delivered water. As such, to ensure that at least the minimum amount of water is being delivered to the tub, the mechanical timer is configured to activate the valve for a slightly longer duration than a minimum duration to account for variations in flow rate and timer accuracy. Accordingly, extra water may be used during each on/off cycle of the valve, which increases water and/or energy consumption of the dishwasher. The extra water can be 10% or more of the minimum amount of water to for proper operation of the dishwasher.
When a known system controller is used to control the valve, the system controller generally provides on/off signals to the valve that are similar to the on/off signals provided by known mechanical timers. At least one known system controller receives feedback from a flowmeter associated with the valve to control an amount of water being delivered to the tub; however, the system controller includes extra input ports and programming to communicate with the flowmeter. As such, additional wires or lines are routed from the flowmeter through a cabinet of the dishwasher to the system controller, which adds complexity to the dishwasher and/or the system controller.
Further, when at least some known dishwashers are operated, extra water is delivered to the tub to wet components within the tub. For example, when a wash cycle is initiated, the tub, contents, racks, and/or a sump are dry. Once these surfaces are wetted and the sump is filled, less water can be used during subsequent fill cycles. However, known mechanical timers and at least some known system controllers perform the same fill cycle for the first fill cycle and for subsequent fill cycles. As such, extra water is being used during each subsequent fill cycle or an insufficient amount of water is being used during the first fill cycle.